Association Between Left Atrial Stiffness Index and Clinical Outcomes in Chronic Heart Failure With Impaired Left Ventricular Systolic Function.

Left atrial (LA) stiffness integrates information related to LA mechanical properties and left ventricular (LV) filling dynamics and may provide a comprehensive assessment of cardiac hemodynamic burden in heart failure (HF). However, its clinical significance in patients with chronic HF and impaired LV systolic function remains unclear. We investigated the association between the LA stiffness index (LASI) and clinical outcomes in patients with chronic HF and impaired LV systolic function. We retrospectively analyzed 1,147 patients with chronic HF and left ventricular ejection fraction (LVEF) <50% who underwent comprehensive echocardiography between January 2018 and March 2023. LASI was calculated as the ratio of E/e' to LA reservoir strain and stratified into tertiles. The primary endpoint was a composite of cardiovascular death or HF hospitalization. Kaplan-Meier analysis and Cox proportional hazards models were used to evaluate the association between LASI and clinical outcomes. During a median follow-up of 34 months, 218 patients experienced the primary endpoint. Event-free survival progressively decreased across LASI tertiles (log-rank p <0.01). After adjustment for age, sex, LVEF, LA volume index, and tricuspid regurgitation velocity, higher LASI remained independently associated with adverse outcomes (hazard ratio 2.41, 95% confidence interval 1.55 to 3.73, p <0.01). This association was consistent across clinically relevant subgroups, including age, diabetes mellitus, LV geometry, and LA size. In conclusion, in patients with chronic HF and impaired LV systolic function, increased LASI was independently associated with cardiovascular death and HF hospitalization, suggesting that LASI may serve as a practical echocardiographic marker reflecting atrial dysfunction and hemodynamic burden.